Search Device, Search Method, and Computer-Readable Recording Medium Storing Search Program

1. A non-transitory computer-readable recording medium storing a program to cause a computer to execute a search method, the search method comprising: providing plural databases sharing management of plural attributes associated with an entity identifier capable of identifying an entity, each of the plural databases storing an entity identifier in association with an attribute value of one of the plural attributes and an attribute name; receiving a search request including plural search conditions, each of the plural search conditions containing a combination of an attribute name and an attribute value; separating the plural search conditions included in the search request into search conditions for individual databases in accordance with an attribute management table, the attribute management table having attribute records containing a database identifier capable of identifying one of the plural databases and an attribute name of an attribute managed in the one of the plural databases; storing, for each database, the search condition and the database identifier in a condition record stored in a condition storage; searching a search result management table by the database identifier and the search condition contained in each of the condition records, the search result management table having result records containing a database identifier of a search database, a first search condition, and a hit count representing an amount of entity identifiers found in a past search, the attribute value managed in association with the entity identifiers in the search database satisfying the first search condition; determining anterior search databases identified with the database identifiers contained in the result records, the result records containing a hit count which is less than or equal to a predetermined amount or a hit count within a predetermined lowest ranks; searching each of the anterior search databases by the search condition contained in the condition record containing the database identifier of the each of the anterior search databases to acquire a first search result including a first entity identifier, the attribute value managed in association with the first entity identifier in the each of the anterior search databases satisfying the search condition for the each of the anterior search databases; determining common entity identifiers included in common in the first search results and generating a new search condition by adding an entity identifier determined to be in common and searching each of posterior search databases to acquire a second search result including second entity identifiers, and where the posterior search database being out of the plural databases other than the anterior search databases, the attribute value managed in association with the second entity identifier in the each of the posterior search databases satisfies the search condition for the each of the posterior search database.

2. The computer-readable recording medium of claim 1 , the search method further including: determining whether any common entity identifiers have been found upon executing the determining common entity identifiers, and terminating without searching the posterior search databases when no common entity identifiers have been found.

3. The computer-readable recording medium of claim 1 , wherein the result record further contains a third entity identifier notified from a presence system when a database out of the plural databases is a presence database managed by the presence system, the attribute value managed in association with the third entity identifier in the presence database satisfying the search condition containing a combination of an attribute name of an attribute managed in the presence database and an attribute value, and the searching each of the anterior search databases includes: acquiring as the first search result the third entity identifier contained in the result record for a presence database when the anterior search database is the presence database.

4. The computer-readable recording medium of claim 3 , wherein the searching each of the posterior search databases includes: extracting fourth entity identifiers stored in the presence databases from result records when the posterior search databases include the presence databases, and searching each of the posterior search databases other than the presence databases by the search condition contained in the condition record, the common entity identifiers, and the fourth entity identifiers.

5. The computer-readable recording medium of claim 3 , the search method further including: updating, upon receiving from the presence system a presence update notification including a second search condition and a fifth entity identifier, the search result management table in accordance with the presence update notification, the attribute value managed in association with the fifth entity identifier in the presence database satisfying the second search condition for the presence database.

6. The computer-readable recording medium of claim 1 , the search method further including: storing, upon searching each of the anterior search databases, in a result record the hit count of the search in the each of the anterior search databases, the result record containing the database identifier of the each of the anterior search databases and the search condition for the each of the anterior search databases.

7. The computer-readable recording medium of claim 1 , wherein the determining anterior search databases includes: determining a maximum value of the hit counts contained in the result records containing the database identifier and the search condition contained in the condition records, determining the predetermined amount on the basis of the maximum value.

8. The computer-readable recording medium of claim 1 , wherein the result record further contains a search count representing a total count of past searches regarding the first search condition contained in the result record, the search method further including: incrementing the search count contained in the result record by one upon searching the database identified with the database identifier contained in the result record by the first search condition contained in the result record, and storing in cache memory the result record containing a search count greater than a predetermined count, wherein the determining anterior search databases includes: determining anterior search databases identified with the database identifiers contained in the result records stored in the cache memory.

9. A search device, the search device comprising: a memory to store a program; and a processor to execute a process based on the program, the process including: providing plural databases sharing management of plural attributes associated with an entity identifier capable of identifying an entity, each of the plural databases storing an entity identifier in association with an attribute value of one of the plural attributes and an attribute name; receiving a search request including plural search conditions, each of the plural search conditions containing a combination of an attribute name and an attribute value; separating the plural search conditions included in the search request into search conditions for individual databases in accordance with an attribute management table, the attribute management table having attribute records containing a database identifier capable of identifying one of the plural databases and an attribute name of an attribute managed in the one of the plural databases; storing, for each database, the search condition and the database identifier in a condition record stored in a condition storage; searching a search result management table by the database identifier and the search condition contained in each of the condition records, the search result management table having result records containing a database identifier of a search database, a first search condition, and a hit count representing an amount of entity identifiers found in a past search, the attribute value managed in association with the entity identifiers in the search database satisfying the first search condition; determining anterior search databases identified with the database identifiers contained in the result records, the result records containing a hit count which is less than or equal to a predetermined amount or a hit count within a predetermined lowest ranks; searching each of the anterior search databases by the search condition contained in the condition record containing the database identifier of the each of the anterior search databases to acquire a first search result including a first entity identifier, the attribute value managed in association with the first entity identifier in the each of the anterior search databases satisfying the search condition for the each of the anterior search databases; determining common entity identifiers included in common in the first search results; and generating a new search condition by adding an entity identifier determined to be in common and searching each of posterior search databases to acquire a second search result including second entity identifiers, and where the posterior search database being out of the plural databases other than the anterior search databases, the attribute value managed in association with the second entity identifier in the each of the posterior search databases satisfies the search condition for the each of the posterior search database.

10. A search method executed by a search device, the search method comprising: providing plural databases sharing management of plural attributes associated with an entity identifier capable of identifying an entity, each of the plural databases storing an entity identifier in association with an attribute value of one of the plural attributes and an attribute name; receiving a search request including plural search conditions, each of the plural search conditions containing a combination of an attribute name and an attribute value; separating the plural search conditions included in the search request into search conditions for individual databases in accordance with an attribute management table, the attribute management table having attribute records containing a database identifier capable of identifying one of the plural databases and an attribute name of an attribute managed in the one of the plural databases; storing, for each database, the search condition and the database identifier in a condition record stored in a condition storage; searching a search result management table by the database identifier and the search condition contained in each of the condition records, the search result management table having result records containing a database identifier of a search database, a first search condition, and a hit count representing an amount of entity identifiers found in a past search, the attribute value managed in association with the entity identifiers in the search database satisfying the first search condition; determining, by the search device, anterior search databases identified with the database identifiers contained in the result records, the result records containing a hit count which is less than or equal to a predetermined amount or a hit count within a predetermined lowest ranks; searching each of the anterior search databases by the search condition contained in the condition record containing the database identifier of the each of the anterior search databases to acquire a first search result including a first entity identifier, the attribute value managed in association with the first entity identifier in the each of the anterior search databases satisfying the search condition for the each of the anterior search databases; determining common entity identifiers included in common in the first search results; and generating a new search condition by adding an entity identifier determined to be in common and searching each of posterior search databases to acquire a second search result including second entity identifiers, and where the posterior search database being out of the plural databases other than the anterior search databases, the attribute value managed in association with the second entity identifier in the each of the posterior search databases satisfies the search condition for the each of the posterior search database.